Differential Diagnosis

The patient's symptoms and test results suggest a complex condition with multiple possible causes. Here's a categorized differential diagnosis:

• Single most likely diagnosis
  • Fibromyalgia: The patient's widespread pain, stiffness, and fatigue, along with the presence of tender points and normal laboratory tests, are consistent with fibromyalgia. The sudden onset of symptoms and the patient's description of pain as "burning/squeezing/achey" also support this diagnosis.
• Other Likely diagnoses
  • Small fiber neuropathy: The patient's symptoms of burning pain, numbness, and pins and needles, particularly in response to stimuli like pants or cool wind, could be indicative of small fiber neuropathy.
  • Vitamin D deficiency: Although the patient's vitamin D level has improved, a history of severe deficiency could contribute to ongoing symptoms like muscle spasms, fatigue, and pain.
  • Autoimmune disorder (e.g., lupus or rheumatoid arthritis): The patient's positive ANA test results and symptoms like joint stiffness and fatigue could suggest an underlying autoimmune condition.
• Do Not Miss (ddxs that may not be likely, but would be deadly if missed)
  • Multiple sclerosis: Although the patient's brain and spine MRIs are clean, the sudden onset of symptoms and the presence of visual processing difficulties could warrant further investigation for multiple sclerosis.
  • Lyme disease: Despite negative testing, the patient's history of a rash and ongoing symptoms could indicate a missed diagnosis of Lyme disease, which can have serious consequences if left untreated.
  • Peripheral artery disease: The patient's symptoms of leg pain and stiffness, particularly with activity, could be indicative of peripheral artery disease, which requires prompt diagnosis and treatment to prevent serious complications.
• Rare diagnoses
  • Adrenoleukodystrophy: The patient's elevated long-chain fatty acid (hexacosanoic acid) level could suggest a rare genetic disorder like adrenoleukodystrophy, which affects the nervous system and adrenal glands.
  • Erythromelalgia: The patient's symptoms of burning pain, particularly in response to stimuli like heat or cool wind, could be indicative of erythromelalgia, a rare disorder characterized by burning pain and redness in the hands and feet.
  • Mitochondrial myopathy: The patient's symptoms of muscle spasms, fatigue, and exercise-induced visual processing difficulties could suggest a mitochondrial myopathy, a rare group of disorders affecting the mitochondria and leading to muscle weakness and other symptoms.